The present invention relates to a method of attaching an article to the inside of a tire cavity. Specifically the invention relates to a method of attaching an electronic microchip to the innerlining of a pneumatic tire.
Recently it has been proposed to provide a pneumatic tire with an electronic microprocessor or microchip which may be used to record and monitor operating parameters such as temperature or temperature history of the tire in use on a vehicle.
Attaching such a microchip to the outer surface of the tire, such as the sidewall, is clearly not a particularly viable option in view of the likelihood of damage due to physical impact or exposure to water or the like. The alternative of attaching the electronic component to the inside of the tire is also problematic since the innerliners of modern tubeless pneumatic tires invariably comprise one or more of a number of highly saturated butyl rubbers which in the cured state exhibit insufficient chemical reactivity to most practical adhesive systems to generate a reliable bond.
Accordingly hitherto it has been proposed to incorporate such a microchip within the tire carcass. One proposal has been to bury the microchip inside the bulky apex rubber in the tire bead region, but this is not found to be satisfactory as it requires the electronic component to withstand the rigors of tire building.
Accordingly it is an object of the present invention to provide a method of securely adhering an article such as an electronic microchip component to the inside of a tubeless pneumatic tire.
According to one aspect of the invention there is provided a method of attaching an article to the inside surface of a pneumatic tire comprising coating an area of the inner surface of an uncured tire carcass with a first layer of flexible adhesive, covering the first layer of adhesive with a removable masking layer comprising a flexible and heat resistant material, curing the tire carcass in a heated tire mould, removing the cured tire from the mould and removing the masking layer to expose the first layer of adhesive, coating a face of the article with a second layer of flexible adhesive and attaching the article to the tire by bringing together the first and second layers of adhesive.
By applying the first layer of adhesive to the inner surface of the tire whilst the rubber is in an uncured state, there exists sufficient reactivity between the adhesive and the rubber surface to assure an adequate bond.